Fixed ball valves have the following advantages :
1. The fluid resistance is small, and its resistance coefficient is equal to the pipe length of the same length. 
2. The structure is simple, small in size and light in weight. 
3. It is compact and reliable. At present, the sealing surface material of the ball valve is widely used in plastic and has good sealing performance. It has also been widely used in vacuum systems. 
4. The operation is convenient, the opening and closing is rapid, and the rotation is 90° from full opening to full closing, which is convenient for long-distance control. 
5. The maintenance is convenient, the ball valve has a simple structure, and the sealing ring is generally movable, and the disassembly and replacement are relatively convenient. 
6. When fully open or fully closed, the sealing surface of the ball and the valve seat is isolated from the medium, and the medium does not cause erosion of the sealing surface of the valve. 
7. Wide range of applications, from small to a few millimeters, up to a few meters, from high vacuum to high pressure can be applied. When the ball is rotated 90 degrees, all the spheres should appear at the entrance and exit, thus cutting off the flow.
Fixed ball valve application range:
The fixed ball valve is suitable for various pipelines of Class150~Class1500, PN16~PN100, JIS 10K~JIS 20K. It is used to cut off or connect the medium in the pipeline. It is made of different materials and can be applied to water, steam and oil respectively. , liquefied gas, natural gas, coal gas, nitric acid, acetic acid, oxidizing medium, urea and other media, widely used in chemical, petroleum, natural gas, metallurgical and other industries, mainly used to cut, distribute and change the flow direction of the medium. .
Fixed ball valve structure features:
1. Open and close without friction. This feature completely solves the problem that the traditional [wiki] valve [/wiki] affects the seal due to friction between the sealing faces.
2. Top-loading structure. The valve installed on the pipeline can be directly inspected and repaired online, which can effectively reduce the parking of the device and reduce the cost.
3, single valve seat design. It eliminates the problem that the cavity medium in the valve affects the safety of use due to abnormal boosting.
4. Low torque design. The specially designed valve stem can be easily opened and closed with a small handwheel valve.
5. Wedge seal structure. The valve is based on the mechanical force provided by the valve stem, and the ball wedge is pressed onto the valve seat to seal, so that the sealing property of the valve is not affected by the change of the pressure difference of the pipeline, and the sealing performance is reliably guaranteed under various working conditions.
6. Self-cleaning structure of the sealing surface. When the ball is tilted away from the valve seat, the fluid in the pipeline passes through the spherical sealing surface at 360°, which not only eliminates the high-speed fluid scouring on the valve seat, but also washes away the accumulation on the sealing surface to achieve self-cleaning. .
Standard Specification for Fixed Ball Valves:
Design and manufacturing standards: GB/T 12237-2007 
Structure length standard: GB/T 12221-2005
Connection flange standard: GB/T 9113
Pressure temperature grade: GB/T 12224-2005
Test inspection standard: GB/T 13927-2008